Fix unused variable warning in compiler/debug.cpp.
Fix unused variable warning in compiler/debug.cpp.

BUG=angle:534

Change-Id: I893e552628c7deba4bc67baae6e5e28b6161c5d4
Reviewed-on: https://chromium-review.googlesource.com/178454
Reviewed-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@chromium.org>
Commit-Queue: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@chromium.org>
Tested-by: Nicolas Capens <51edc787c30f24c4904e8ffbb5523c3a9f7a451d@chromium.org>

geekboxzone/lollipop_external_chromium_org_third_party_angle,geekboxzone/lollipop_external_chromium_org_third_party_angle,xin3liang/platform_external_chromium_org_third_party_angle,xin3liang/platform_external_chromium_org_third_party_angle,jgcaaprom/android_external_chromium_org_third_party_angle,android-ia/platform_external_chromium_org_third_party_angle,jgcaaprom/android_external_chromium_org_third_party_angle,xin3liang/platform_external_chromium_org_third_party_angle,MIPS/external-chromium_org-third_party-angle,android-ia/platform_external_chromium_org_third_party_angle,vvuk/angle-old,jgcaaprom/android_external_chromium_org_third_party_angle,vvuk/angle-old,jgcaaprom/android_external_chromium_org_third_party_angle,geekboxzone/lollipop_external_chromium_org_third_party_angle,android-ia/platform_external_chromium_org_third_party_angle,MIPS/external-chromium_org-third_party-angle,android-ia/platform_external_chromium_org_third_party_angle,geekboxzone/lollipop_external_chromium_org_third_party_angle,MIPS/external-chromium_org-third_party-angle,vvuk/angle-old,vvuk/angle-old,xin3liang/platform_external_chromium_org_third_party_angle,MIPS/external-chromium_org-third_party-angle